Real Time Clock Modules - Seiko Epson
RTC-72421/72423
Features
• Built-in quartz crystal makes regulation unnecessary
and allows for easy design
• ALE INPUT terminal available for 8048, 8051 and
8085 series
• Incorporates built-in time counters (year, month,
week, day)
• 12hr/24hr clock switchcover function and automatic
leap year setting
• 30 seconds error adjustment function
• READ, WRITE, HOLD, STOP, RESET and CHIP SELECT
inputs
• The CMOS IC boasts low current consumption &
features a backup function
• 18 pin dual-in-line package
Absolute Max. Rating
Item
Symbol Condition
Specification
Unit
• Pin and function are compatible with the SMC 5242C
Supply voltage
Input and Output voltage
Storage temp.
VDD
VI/O
TSTG
Ta=25°C
Ta=25°C
RTC-72421
RTC-72423
-0.3 ~ +7.0
GND -0.3 ~ VDD +0.3
-55 ~+85
V
V
°C
Terminal Connection
-55 ~ +125
Under 260°C within 10S (lead part)
(package should be less than 150°C)
RTC-72421
RTC-72423
Soldering condition
TSOL
Under 260°C within 10S x 2
time under 230°C withhin 3 min
Operating Voltage
Item
Symbol Condition
Specification
Unit
Operating voltage
VDD
TOPR
VDH
tCDR
tR
-
-
-
4.5 ~ 5.5
-40 ~ +85
2.0 ~ 5.5
2.0 min.
V
°C
V
Operating temperature
Data holding voltage
CSI data holding time
Operating restoring time
µS
Refer to the data
holding timing
Frequency and Current Consumption Characteristics
Item
Symbol
Condition
Specification Unit
72421A
±10
Ta=25°C
VDD=5V
72421B
72423A
7243B
±50
ppm
±20
±50
Frequency tolerance
∆f/fo
Frequency temperature
characteristics
-10 ~ +70°C,
(25°C reference
±10/-120
ppm
Dimensions (mm)
temperature)
Aging
Shock resistance
fa
S.R.
VDD=5V, Ta25°C, 1st year
±5 max.
±5 max.
ppm
ppm
Drop test of 3 times on a hard
board from 75cmheight of
300G x 0.3mS x 1/2 sine wave
x 3 directions
Current consumption
IDD
IDD
1
2
CSI≥ov VDD=5V
10 max.
5 Max.
µA
µA
VDD=2V
Electrical Characteristics
Item
Symbol Condition Min Typ.
Max. Unit Applicable terminal
“H” Input Voltage (1)
“L” Input Voltage (1)
Input leakage current (1)
VIH1
VIHL
IIK1
-
-
2.2
-
-
-
-
-
V
All inputs
0.8
1/-1
other than CSI
µA
Input other than
D2 ~ D3
1
V =VDD/0V
Input leakage current (2)
“L” output voltage (1)
“H” output voltage
“L” output voltage (2)
OFF leak current
ILK2
VOL1
VOH
VOL2
IOFFLK
C1
-
-
-
10/-10
D0 ~ D3
D0 ~ D3
IOL=2.5mA
IOH=-400µA
IOL=2.5mA
-
2.4
-
0.4
-
V
-
-
0.4
10
-
V
STD.P
CSI1
DD
V1=V /0V
-
-
µA
pF
Input capacity
Input Frequency
1MHz
-
5
“H” Input Voltage (2)
“L” Input Voltage (2)
VIH2
VIH2
VDD=2~5.5V 4/5VDD
-
-
-
-
V
1/5VDD
TEL: +44 1635 528520 FAX: +44 1635 528443
